18c2ecf20Sopenharmony_ci# SPDX-License-Identifier: GPL-2.0-only 28c2ecf20Sopenharmony_ci 38c2ecf20Sopenharmony_ciconfig CACHEFILES 48c2ecf20Sopenharmony_ci tristate "Filesystem caching on files" 58c2ecf20Sopenharmony_ci depends on FSCACHE && BLOCK 68c2ecf20Sopenharmony_ci help 78c2ecf20Sopenharmony_ci This permits use of a mounted filesystem as a cache for other 88c2ecf20Sopenharmony_ci filesystems - primarily networking filesystems - thus allowing fast 98c2ecf20Sopenharmony_ci local disk to enhance the speed of slower devices. 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ci See Documentation/filesystems/caching/cachefiles.rst for more 128c2ecf20Sopenharmony_ci information. 138c2ecf20Sopenharmony_ci 148c2ecf20Sopenharmony_ciconfig CACHEFILES_DEBUG 158c2ecf20Sopenharmony_ci bool "Debug CacheFiles" 168c2ecf20Sopenharmony_ci depends on CACHEFILES 178c2ecf20Sopenharmony_ci help 188c2ecf20Sopenharmony_ci This permits debugging to be dynamically enabled in the filesystem 198c2ecf20Sopenharmony_ci caching on files module. If this is set, the debugging output may be 208c2ecf20Sopenharmony_ci enabled by setting bits in /sys/modules/cachefiles/parameter/debug or 218c2ecf20Sopenharmony_ci by including a debugging specifier in /etc/cachefilesd.conf. 228c2ecf20Sopenharmony_ci 238c2ecf20Sopenharmony_ciconfig CACHEFILES_HISTOGRAM 248c2ecf20Sopenharmony_ci bool "Gather latency information on CacheFiles" 258c2ecf20Sopenharmony_ci depends on CACHEFILES && PROC_FS 268c2ecf20Sopenharmony_ci help 278c2ecf20Sopenharmony_ci 288c2ecf20Sopenharmony_ci This option causes latency information to be gathered on CacheFiles 298c2ecf20Sopenharmony_ci operation and exported through file: 308c2ecf20Sopenharmony_ci 318c2ecf20Sopenharmony_ci /proc/fs/cachefiles/histogram 328c2ecf20Sopenharmony_ci 338c2ecf20Sopenharmony_ci The generation of this histogram adds a certain amount of overhead to 348c2ecf20Sopenharmony_ci execution as there are a number of points at which data is gathered, 358c2ecf20Sopenharmony_ci and on a multi-CPU system these may be on cachelines that keep 368c2ecf20Sopenharmony_ci bouncing between CPUs. On the other hand, the histogram may be 378c2ecf20Sopenharmony_ci useful for debugging purposes. Saying 'N' here is recommended. 388c2ecf20Sopenharmony_ci 398c2ecf20Sopenharmony_ci See Documentation/filesystems/caching/cachefiles.rst for more 408c2ecf20Sopenharmony_ci information. 41